U.S. patent application Ser. No. 11/559,507, filed Nov. 14, 2006, discloses a nonwoven material for use as, among other things, a wound dressing. In general, this nonwoven material comprises bulked filaments that are fixed into a 3-dimensional structure. Additionally, this nonwoven is characterized by having a uniform density throughout its thickness and by having filaments that protrude beyond its external surface, see FIG. 1. Moreover, this application discloses that this nonwoven may be subsequently calendered.
Nonwoven is a term of art that refers to a manufactured sheet, batting, webbing, or fabric that is held together by various methods. Those methods include, for example, fusion of fibers (e.g., thermal, ultrasonic, pressure, and the like), bonding of fibers (e.g., resins, solvents, adhesives, and the like), and mechanical entangling (e.g., needle-punching, entangling, and the like). The term is sometimes used broadly to cover other structures such as those held together by interlacing of yarns (stitch bonding) or those made from perforated or porous films. The term excludes woven, knitted, and tufted structures, paper, and felts made by wet milling processes. In its most common usage, the term includes fibrous structures made by such processes as dry, wet, or air-laying (with or without one of the methods of holding the fibers together mentioned above), needle-punching, spunbond or meltblown processes, and hydroentangling (spunlacing). In the dry, wet, air-laying, and hydroentangling (spunlacing) processes, staple fibers are used in the manufacture of the nonwoven material. In the spunbond and meltblown processes, molten polymer is extruded onto a moving belt; the fibers of these types of nonwovens may be filaments.
While the nonwoven material disclosed in U.S. patent application Ser. No. 11/559,507 is an advancement in the art, there is still a need to improve that material.